She needn’t worry. The research suggesting any fertility risk from laptops is sparse, and it applies more to men than to women. A small 2004 study found that after cradling a laptop in their laps for an hour, men’s scrotal temperature increased by 4 to 5 degrees Fahrenheit (2 to 3 Celsius). While other studies suggest that’s enough to potentially reduce the testicles’ sperm production, it’s about the same temperature increase that a man would get from simply sitting with his thighs together for an hour, or riding in a car for two hours. A greater, though still remote, danger is that some laptops can get hot enough to cause burns. So test the bottom of the machine with a finger before placing it on exposed skin.